1. Field of the Invention
This invention relates to bulk material handling and more particularly to an apparatus into which particulate or comminuted material contents of rupturable bags may be charged for further material handling, generally referred to in the relevant industry as filter bag dump stations.
2. Description of the Prior Art
In the prior art, there has been developed and in widespread use, a type of apparatus into which particulate material contents of rupturable bags may be charged for further handling such as pneumatic conveying, processing, storing and the like. Such type of apparatus generally includes a hopper having a grate disposed across an inlet opening thereof into which the contents of bagged material may be charged, a filtering unit having an inlet communicating with the interior of the hopper and a blower for drawing airborne particles produced by the charging of such material into the hopper from the vicinity of the work area and conveying them through the filter unit to prevent such particles from escaping into the ambient atmosphere and possibly causing environmental problems in a work area. An example of such an apparatus is illustrated and described in U.S. Pat. No. 4,889,452.
The type of filter unit provided in such an apparatus typically consists of a tube sheet forming a wall of an air plenum, a plurality of elongated, tubularly configured cages mounted on the tube sheet with the interiors thereof communicating with the air plenum through openings in the tube sheet, and filter media consisting of fabric or felt materials disposed on the tubular cages. A motor driven centrifugal blower typically is employed to create an air flow for capturing airborne particles at the charging inlet of the hopper, conveying such particles through the filtering media for removal and discharging the clean air into the ambient atmosphere. Although such particle filtration process has been highly effective in capturing and removing a substantial portion of the airborne particles produced in conventional bag dump stations of the type described, it has been found that such conventional stations are not always sufficiently effective in removing particulates of less than one micron size in compliance with more stringent federal and state dust control requirements.